Deep Brain And Spinal Cord Stimulation May Arouse People In A Minimally Conscious Or Persistent Vegetative State

Doctor Reviewing Spinal Model

Persistent vegetative state (a state of wakefulness with no consciousness) and minimally conscious state (short periods of consciousness) are difficult disorders to treat. Recoveryis rare after three months, and is unlikely after twelve months.

Studies have shown that deep brain stimulation and spinal cord stimulation are therapies can sometimes induce arousal in people in a vegetative or a minimally conscious state. Deep brain stimulation involves placing an electrode that sends electrical impulses deep within certain areas of the brain in order to stimulate neural activity. Spinal cord stimulation work similarly, but the electrode is placed in the epidural space of the vertebrae.

A recent study of 107 people in a vegetative state and 21 people in a minimally conscious state found that deep brain stimulation at the mesencephalic reticular formation or the centromedian complex applied for 30 minutes every 2 to 3 hours during the day helped to restore function for people in either a vegetative and minimally conscious state. The study also found that spinal cord stimulation placed at the cervical vertebrae C2 to C4 for 5 minutes every 30 minutes during the day induced arousal in people in a minimally conscious state.

The study found that deep brain stimulation immediately produced the following arousal signs from people in a vegetative state:
• Opened eyes (with dilated pupils)
• Increased blood pressure
• Slight movement in the extremities
• Increased cerebral blood flow

In addition, spinal cord stimulation immediately produced:
• Increased muscle twitches
• Increased cerebral blood flow

People in a vegetative state who experience the long-term use (4-12 months) of deep brain stimulation were able to communicate and follow simple directions, although most remained bedridden.

The long-term use of deep brain and spinal cord stimulation on people in a minimally conscious state produced interactive communication and the functional use of two different objects.

However, only patients who reached a certain threshold of resting brain function based on electrophysiological evaluation responded to deep brain or spinal cord stimulation. Those who did not reach the minimum threshold from the electrophysiological evaluation did not show a significant response to the therapies.

Yamamoto T, Katayama Y, Obuchi T, et al. DBS and SCS for vegetative and minimally conscious state. World Neurosurgery. (June 2012).